During a period commencing in the early 1960's, a great deal of development work has been done upon balers which form large, cylindrical bales of hay or other forage crops, either by rolling a windrow of hay into a bale on the ground, as by feeding the windrow into a baling chamber and rolling the bale in the chamber. Either type of apparatus may be used to produce bales which are four or five feet in diameter and six or eight feet long, and which weigh up to several tons.
Formation of a satisfactory bale requires that the ends of the bale (the sides relative to the line of travel of the baler) be confined between smooth metal plates which form the sides of the baling chamber so as to minimize the amount of material projecting from the ends of the bale. A preferred baler structure for accomplishing this is the rotatable discs disclosed in U.S. Pat. No. 4,103,475 which are there illustrated in a ground engaging baler but which are equally applicable to a chamber type baler of the general type disclosed in U.S. Pat. No. 3,848,526.
Confining the ends of the bale between smooth metal plates that define the sides of the baling chamber has a tendency to interfere with the release of a finished bale from the baling chamber, and at least in the case of a chamber type baler it increases a power required to discharge the bale.